Seed-Layer-Free Atomic Layer Deposition of Highly Uniform Al 2 O 3 Thin Films onto Monolayer Epitaxial Graphene on Silicon Carbide

Emanuela Schilirò, Raffaella Lo Nigro, Fabrizio Roccaforte, Ioannis Deretzis, Antonino La Magna, Angelo Armano, Simonpietro Agnello, B. Pécz, Ivan G. Ivanov, Rositsa Yakimova, Filippo Giannazzo

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Atomic layer deposition (ALD) is the method of choice to obtain uniform insulating films on graphene for device applications. Owing to the lack of out-of-plane bonds in the sp 2 lattice of graphene, nucleation of ALD layers is typically promoted by functionalization treatments or predeposition of a seed layer, which, in turn, can adversely affect graphene electrical properties. Hence, ALD of dielectrics on graphene without prefunctionalization and seed layers would be highly desirable. In this work, uniform Al 2 O 3 films are obtained by seed-layer-free thermal ALD at 250 °C on highly homogeneous monolayer (1L) epitaxial graphene (EG) (>98% 1L coverage) grown on on-axis 4H-SiC(0001). The enhanced nucleation behavior on 1L graphene is not related to the SiC substrate, but it is peculiar of the EG/SiC interface. Ab initio calculations show an enhanced adsorption energy for water molecules on highly n-type doped 1L graphene, indicating the high doping of EG induced by the underlying buffer layer as the origin of the excellent Al 2 O 3 nucleation. Nanoscale current mapping by conductive atomic force microscopy shows excellent insulating properties of the Al 2 O 3 thin films on 1L EG, with a breakdown field > 8 MV cm −1 . These results will have important impact in graphene device technology.

Original languageEnglish
Article number1900097
JournalAdvanced Materials Interfaces
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

Atomic layer deposition
Silicon carbide
Graphene
Seed
Monolayers
Thin films
Nucleation
Buffer layers
Atomic force microscopy
Electric properties
Doping (additives)
Adsorption
Molecules

Keywords

  • atomic force microscopy
  • atomic layer deposition
  • epitaxial graphene
  • SiC

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Seed-Layer-Free Atomic Layer Deposition of Highly Uniform Al 2 O 3 Thin Films onto Monolayer Epitaxial Graphene on Silicon Carbide . / Schilirò, Emanuela; Lo Nigro, Raffaella; Roccaforte, Fabrizio; Deretzis, Ioannis; La Magna, Antonino; Armano, Angelo; Agnello, Simonpietro; Pécz, B.; Ivanov, Ivan G.; Yakimova, Rositsa; Giannazzo, Filippo.

In: Advanced Materials Interfaces, 01.01.2019.

Research output: Contribution to journalArticle

Schilirò, E, Lo Nigro, R, Roccaforte, F, Deretzis, I, La Magna, A, Armano, A, Agnello, S, Pécz, B, Ivanov, IG, Yakimova, R & Giannazzo, F 2019, ' Seed-Layer-Free Atomic Layer Deposition of Highly Uniform Al 2 O 3 Thin Films onto Monolayer Epitaxial Graphene on Silicon Carbide ', Advanced Materials Interfaces. https://doi.org/10.1002/admi.201900097
Schilirò, Emanuela ; Lo Nigro, Raffaella ; Roccaforte, Fabrizio ; Deretzis, Ioannis ; La Magna, Antonino ; Armano, Angelo ; Agnello, Simonpietro ; Pécz, B. ; Ivanov, Ivan G. ; Yakimova, Rositsa ; Giannazzo, Filippo. / Seed-Layer-Free Atomic Layer Deposition of Highly Uniform Al 2 O 3 Thin Films onto Monolayer Epitaxial Graphene on Silicon Carbide In: Advanced Materials Interfaces. 2019.
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